A typical motor vehicle comprises a vehicle body mounted upon tour wheels. Generally, the motor vehicle includes a suspension system providing for suspension between the vehicle body and the wheels, to allow for a smooth ride. Such a system may, for example, include leaf springs or other conventional arrangements.
In normal use of a motorized vehicle, the load and distribution of the load carried by the suspension system may vary. For example, a trailer or the like might be attached to the rear of the vehicle, causing an increase in weight load carried by a rear portion of the vehicle suspension system. Further, loading of the vehicle body, upon the springs, may be varied by varying numbers and/or distributions of passengers within the vehicle, and the carrying of cargo by the vehicle.
Under varying loads, the attitude of the vehicle body relative to the wheels may be changed. For example, if the rear trunk compartment of a motorized vehicle is heavily loaded with luggage or the like, the rear portion of the body may sink with the front portion of the body raising somewhat, with respect to the wheels and the ground. A similar effect may be encountered if a trailer is attached to the rear of the vehicle.
Generally, conventional motor vehicles are manufactured such that varying attitudes of the vehicle body, relative to the wheels, due to load variations, do not present a substantial problem to vehicle performance. That is, generally, arrangements have been developed permitting adequate compensation to the varying vehicle body position, to permit appropriate vehicle control.
In at least one area, however, problems have developed. This generally relates to vehicle headlight alignment.
Most motorized vehicles include a set of headlights. These headlights are adjusted, generally, to be aimed at a portion of the road surface a selected distance in front of the vehicle, to provide appropriate illumination for driving at night. Often high beam and low beam systems are utilized, to provide both near and distance viewing.
Two important parameters control and determine appropriate aiming of the headlights. The first is that the headlights, particularly low beam headlights, should be aimed sufficiently downwardly at the road surface, so that drivers of oncoming vehicles will not be temporarily blinded by the vehicle lights. Secondly, the headlights must be oriented in an appropriate position to provide adequate illumination of the road surface, for safe vehicle operation. This generally requires aiming at or near the road surface a selected distance in front of the vehicle.
The headlight systems are mounted within the vehicle body, which floats upon the suspension system. Thus, as the vehicle body orientation or attitude shifts relative to varying loads, headlight positioning also shifts. As a result, proper headlight adjustment may be disrupted when cargo or passengers are put in a vehicle body, or when a trailer is attached to the vehicle.
For example, consider an empty vehicle with its headlights appropriately adjusted at a selected position on a road surface. Should a heavy load be placed in a rear portion of the vehicle body, the rear portion will sink, and the front portion of the vehicle body will be raised somewhat. The result of this is that the headlights will be aimed even further down the road surface, possibly providing for inappropriate and unsafe illumination of the road surface, and also possibly interfering with the vision of operators of oncoming cars.
The problem, then, is generally created by the suspension system, which permits the vehicle body to reorient in response to load. What has been needed is a system by which headlight alignment can be adjusted to compensate for such reorientation.
Numerous systems have been developed and might be suggested, for headlight alignment. However they have not been completely desirable for a number of reasons. For example, if headlight adjustment were made strictly with response to the horizontal, through some sort of leveling means, then proper headlight alignment would generally only be achieved if the adjustment was made while the vehicle was resting on a flat, i.e., not inclined, surface.
It would also be preferred that the system operate through the utilization of relatively inexpensive mechanical and electrical components so that it can be included or added as a feature in even relatively inexpensive vehicles, and will operate under a variety of climactic and weather conditions.